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The University of Michigan Biological Station lies on lake-border plains in the transition zone between the mixed hardwood and boreal forests. The UMBS~Flux study site lies on level to gently sloping high outwash plain derived from glacial drift, with the gradually ascending slope of an interlobate moraine lying ~1 km to the south. Soils are predominantly excessively drained spodosols. Bigtooth aspen (Populus grandidentata) and trembling aspen (P. tremuloides) dominate within a 1 km radius of the eddy-covariance tower, but with significant representation by red oak (Quercus rubra), beech (Fagus grandifolia), red maple (Acer rubrum), white pine (Pinus strobus), and hemlock (Tsuga canadensis) as well. Understory is dominated by bracken fern (Pteridium aquilium) and saplings of red maple, red oak, beech, and white pine. The presettlement white pine, red pine, hemlock forest was cut around 1880, and the area disturbed repeatedly by fire until 1923. Some quantitative descriptors of the physical, vegetational, and soil environments are included in the two tables, below. Link to detailed vegetation and sampling plot maps.
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Physical:
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Latitude
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45o 35' N
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Longitude
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84o 42' W
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Mean ann. temp. (C)
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6.2
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Annual N mineralization
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11
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Annual precipitation (mm)
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750
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Slope (%)
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1-7
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Stand:
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Stand age (yr)
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90
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Canopy height (m)
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20
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LAI
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3.7
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Basal area (m2 ha-1)
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23.7
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Max dbh (cm)
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62
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Mean dbh (cm)
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14
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Soils:
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%sand/silt/clay
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93/6/1
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Texture
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loamy med. sands
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Classification
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entic Haplorthod
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pH
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~4.8
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Some quantitative descriptors of the UMBS~Flux site including features of the physical, vegetational, and soil environment.
Biomass distribution (kg/ha) within the 60 m Ameriflux plot, 1997.
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Tree Species
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Leaves and twigs
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Live branches
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Dead branches
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Bole
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Total
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Acer rubrum
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349
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1,575
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298
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8,936
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11,158
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Amelanchier sp.
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0
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0
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0
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2
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2
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Betula papyrifera
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237
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1,072
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2,997
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7,783
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12,089
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Fagus grandifolia
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12
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85
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167
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274
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538
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Pinus resinosa
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36
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47
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17
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403
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504
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Pinus strobus
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2,027
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5,608
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8
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5,618
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13,261
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Populus grandidentata
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1,014
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6,184
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1,992
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57,460
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66,649
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Populus tremuloides
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2
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6
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3
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45
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56
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Quercus rubra
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507
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4,019
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742
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16,029
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21,297
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Grand Total
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4,184
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18,597
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6,223
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96,550
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125,554
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